Artificial arm



Feb. 8, 1955 J. c. FLYNN ARTIFICIAL ARM Filed July 2. 1953 FIG. 2

Iii

FIG. 3

INVENTOR.

JOHN C. FLYNN ATTORNEY United States Patent' ARTIFICIAL ARM John C. Flynn, South Williamsport, Pa.

Application July 2, 1953, Serial No. 365,728

7 Claims. (Cl. 312.3)

This invention relates to artificial arms and it relates more particularly to improved means for connecting the control cords to the forearm portions of artificial arms in such arms as are provided for cases in which the amputation was above the elbow.

In artificial arms of the character aforesaid, it has been customary to actuate the forearm by means of a cord having one end connected thereto and having the other end extending to a shoulder harness, the arrangement being such that when the stump of the upper arm, to which the artificial arm is secured, is moved forwardly, the cord connected to the forearm will cause the same to be raised, slight variations in the relative movement in the forearm portion being obtainable by movement of the shoulder, which movement is transmitted through the cord to the forearm portion of the artificial arm.

However, when the cord is connected directly to the forearm portion of the artificial arm the movement sometimes is awkward and the forearm portion of the artificial arm is not brought to the desired position. By reason of the foregoing, various devices have been suggested for the purpose of varying the initial position and the movementof the forearm, but the same when practical have been expensive, complicated, and quite likely to become disarranged.

The principal object of the present invention is to provide a simple, inexpensive and efiicient mechanism adapt-- ed to be placed within the forearm portion of an artificial arm whereby a better reach is obtainable, and whereby the position of the forearm portion with respect to the upper arm portion can be varied under the control of the user, and which also is so constructed and arranged whereby the connection of the control cord to the forearm portion of the artificial arm may be rendered flexible whenever it is desirable to do so.

The nature and characteristic features of the present invention will be more readily understood from the following description, taken in connection with the accompanying drawing forming part hereof, in which:

Figure 1 is a transverse section of the forearm portion of an artificial arm, having mounted therein mechanism and devices embodying the main features of the present invention;

Fig. 2 is a longitudinal section taken approximately on the line 22 of Fig. 1;

Fig. 3 is a similar section taken approximately on the line 3-3 of Fig. l; and F Fig. 4 is a similar section taken approximately on the line 4-4 of Fig. 1.

It should, of course, be understood that the description and drawing herein are illustrative merely, and that various modifications and changes may be made in the arrangement and devices disclosed without departing from the spirit of the invention.

Referring to the drawing, in the particular embodiment of the invention therein shown, 10 is a part of the forearm portion of an artificial arm which is pivoted, in the usual manner (not shown) to the upper arm portion which is secured to the arm stump of the user. The forearm portion 10 is provided at a suitable location, on each side thereof, with bearings 11 and 12, respectively, in which a shaft 13 is journaled.

Secured to the shaft 13 is a sheave 14, in the groove 15 of which the end portion of the control cord 16 is wound. The extreme end of said cord 16 is secured to the sheave 14 by passing the same through an aperture extending through from the groove 15 of the sheave 14 to one of 2,701,371 Patented Feb. 8, 1955 'ice the outer faces thereof where the cord is knotted as at 17.

The cord 16 passes through an eyelet 18 in the wall of the part 10 of the forearm portion of the artificial arm, and thence extends to the shoulder harness (not shown) or other device to which it is secured in the usual manner.

The shaft 13, when free, is constrained to rotate in a direction to wind the cord 16 in the groove 15 of the sheave 14 by means of a spring 19 made of flat metal shaped in spiral form, having one end secured in a slot 20 in the shaft 13, and having its other end secured as, for example, by means of a rivet 21 to the wall of the part 10 of the forearm portion of the artificial arm in which the aforesaid parts are mounted.

The shaft 13 also has secured thereon a disc 22 having a plurality of radially disposed apertures 23 adapted to alternatively receive the complementally shaped teat 24 at the inner end of the stud 25.

A collar 26 is mounted adjacent the inner end of the stud 25, and a coil spring 27 surrounding the stud 25 has one end bearing against said collar 26. The other end of the spring 27 bears against the interior surface of the part 10 of the forearm portion of the artificial arm in which the aforesaid parts are mounted.

The stud 25 is slidably and rotatively mounted in a bearing member 28, the outer face of which is provided with a cam surface 29 upon which bears a pin 30 mounted in and extending outwardly from the stud 25, the arrangement being such that when the stud 25 is rotated, the innermost end thereof will be retracted against the tension of the coil spring 27 as the pin 30 rises upon the cam surface 29 of the bearing member 28.

The outer end of the stud 25 is provided with a knurled head portion 31 to facilitate the actuation of the stud 25 for its intended purpose.

The foregoing arrangement is such that when the stud 25 is rotated, and the pin 30 rises to the top of the cam surface 29 provided on the outer face of the bearing member 28 the teat portion 24 of the stud 25 will be withdrawn from engagement with the holes 23 in the disc 22 whereby the cord 16 will be under the flexible control of the spiral spring 27 as long as the pin 30 extending sidewise from the stud 25 remains upon the outermost portion of the cam surface 29 of the bearing member 28.

There is thus provided a control for the forearm portion of an artificial arm which is so constructed and arranged that the same may be adjusted to bring the forearm to various initial angular positions with respect to the upper arm portion of the artificial arm, which mechanism may be released whereby the forearm portion may be flexibly connected to said forearm portion when desired.

I claim:

1. In an artificial arm, the means for connecting an actuating cord thereto which comprises a transversely extending shaft journaled in a part of said arm structure, a sheave secured to said shaft having a groove in which a portion of the actuating cord is wound, the end of said actuating cord being secured to a portion of the sheave, a spiral spring adapted to impart torsional tension to the shaft, said spring having one end secured to the shaft and the other end secured to a wall of the arm structure, and manually operable means for locking the shaft against rotation at desired positions about the axis thereof.

2. In an artificial arm, the means for connecting an actuating cord thereto which comprises a transversely extending shaft journaled in a part of said arm structure, a. sheave secured to said shaft having a groove in which a portion of the actuating cord is wound, the end of said actuating cord being secured to a portion of the sheave, a spiral spring adapted to impart torsional tension to the shaft, said spring having one end secured to the shaft and the other end secured to a wall of the arm structure, a disc mounted on and secured to the shaft having a plurality of spaced apertures, a bearing member secured to a wall of the arm structure, a stud movably mounted in said bearing member having a portion adapted to selectively engage one of the apertures in the disc, and means for holding the stud retracted thereby to permit the actuing the same to the desired position for locking or unlocking the shaft.

3. In an artificial arm, the means for connecting an actuating cord thereto which comprises a transversely extending shaft journaled in a part of said arm structure, a sheave secured to said shaft having a groove in which a portion of the actuating cord is wound, the end of said actuating cord being secured to a portion of the sheave, a. spiral spring adapted to impart torsional tension to the shaft, said spring having one end secured to the shaft and the other end secured to a wall of the arm structure, a disc mounted on and secured to the shaft having a plurality of spaced apertures, a bearing member secured to a wall of the arm structure, a stud movably mounted in said bearing member having a portion adapted to selectively engage one of the apertures in the disc, a spring normally impelling said stud to the engaging position, and means for holding the stud retracted thereby to permit the actuating cord to be flexibly controlled by said spiral spring, and the stud having an exteriorly disposed head for moving the same to the desired position for locking or unlocking the shaft.

4. In an artificial arm, the means for connecting an actuating cord thereto which comprises a transversely extending shaft journaled in a part of said arm structure, a sheave secured to said shaft having a groove in which a portion of the actuating cord is wound, the end of said actuating cord being secured to a portion of the sheave, a spiral spring adapted to impart torsional tension to the shaft, said spring having one end secured to the shaft and the other end secured to a wall of the arm structure, a disc mounted on and secured to the shaft having a plurality of spaced apertures, a bearing member secured to a wall of the arm structure, a stud slidably and rotatively mounted in said bearing member having a portion adapted to selectively engage one of the apertures in the disc, a spring normally impelling said stud to the engaging position, the bearing member having a cam surface on its outer face, and the stud having a projecting pin engaging said cam surface whereby the stud may be held retracted and thus permit the actuating cord to be flexibly controlled by said spiral spring, and the stud having an exteriorly disposed head for rotating the same to the desired position for locking or unlocking the shaft.

5. In an artificial arm, the means for connecting an actuating cord thereto which comprises a transversely extending shaft journaled in a part of said arm structure,

a sheave secured to said shaft having a groove in which a portion of the actuating cord is wound, the end of said actuating cord being secured to a portion of the sheave, a spring adapted to impart torsional tension to the shaft, a disc mounted on and secured to the shaft having a plurality of spaced apertures, a bearing member secured to a wall of the arm structure, a stud movably mounted in the structure having a portion adapted to selectively engage one of the apertures in the disc, a spring normally impelling said stud to the engaging position, and means whereby the stud may be held retracted and thus permit the actuating cord to be flexibly controlled by the spring.

6. In an artificial arm, the means for connecting an actuating cord thereto which comprises a transversely extending shaft journaled in a part of said arm structure, a sheave secured to said shaft having a groove in which a portion of the actuating cord is wound, the end of said actuating cord being secured to a portion of the sheave, a spring adapted to impart torsional tension to the shaft, a disc mounted on and secured to the shaft having a plurality of spaced apertures, a stud movably mounted in the structure having a portion adapted to selectively engage one of the apertures in the disc, a spring normally impelling said stud to the engaging position, and means whereby the stud may be held retracted and thus permit the actuating cord to be flexibly controlled by the spring connected to the shaft, said means including an exteriorly disposed head for moving the stud to the desired position for locking or unlocking the shaft.

7. In an artificial arm, the means for connecting an actuating cord thereto which comprises a transversely extending shaft journaled in a part of said arm structure, a sheave secured to said shaft having a groove in which a portion of the actuating cord is wound, the end of said actuating cord being secured to a portion of the sheave, and a spiral spring adapted to impart torsional tension to the shaft, said spring having one end secured to the shaft and the other end secured to a wall of the arm structure.

References Cited in the file of this patent UNITED STATES PATENTS Re. 14,939 Anderson et a1. Aug. 31, 1920 1,278,106 Caron Sept. 10, 1918 1,365,646 Adams Jan. 18, 1921 2,626,398 Grindle et a1. Jan. 27, 1953 

